Board with cholesteric layer and display having the board

• US 7,256,847 B2
• Filed: 11/11/2002
• Issued: 08/14/2007
• Est. Priority Date: 11/07/2001
• Status: Expired due to Fees

• Current Assignee: Dai Nippon Printing Company Limited
• Original Assignee: Dai Nippon Printing Company Limited
• Inventors: Kashima, Keiji
• Primary Examiner(s): Nelms; David
• Assistant Examiner(s): NGUYEN, THANH NHAN P
• Application Number:
  US10/250,650
• Publication Number:
  US 20040051830A1
• Time in Patent Office: 1,737 Days
• Field of Search: 349/115, 349/98, 349113-114, 349/106
• US Class Current: 349/115
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 2201/343 cholesteric liquid crystal reflector
• CPC Class Codes: G02F 2203/09 transflective

Abstract

In view of the above problems of the prior art, the present invention has been made, and an object of the present invention is to provide a board, which is free from coloring, has high color tone quality, can realize a bright display screen, and imposes no significant restriction on the provision of an electric circuit, and a display device comprising the board, and further provides a liquid crystal display board, which is excellent in color contrast between transmission display and reflection display, and a semi-transmission color liquid crystal display device comprising the liquid crystal display board. A board according to the invention comprises a light transparent substrate and a cholesteric layer provided on the substrate and provided with an optical window of a predetermined pattern.

Claims

1. A board, comprising:

a light transparent substrate; and

a cholesteric layer provided on the substrate;

wherein the cholesteric layer is provided with an optical window portion of a predetermined pattern where the cholesteric layer is absent, and

circularly polarized light is reflected on the cholesteric layer, and transmitted in the optical window portion.

2. The board according to claim 1, wherein a reflectance of circularly polarized light from the cholesteric layer is from 90 to 100%.

3. A semi-transmission liquid crystal display device comprising the board according to claim 1.

4. The semi-transmission liquid crystal display device according to claim 3, wherein an electric circuit is provided on a light transparent substrate-side of the cholesteric layer.

5. The semi-transmission liquid crystal display device according to claim 3, further comprising:

a first color filter layer provided on at or above an upper part of the cholesteric layer; and

a second color filter layer provided at or above an upper part of the optical window portion.

6. The semi-transmission liquid crystal display device according to claim 5, wherein the second color filter layer is provided in the optical window portion of the cholesteric layer.

7. The semi-transmission liquid crystal display device according to claim 3, wherein:

a color filter layer is provided at or above an upper part of the cholesteric layer; and

a first light transmittance of the color filter layer in a portion corresponding to the optical window portion is higher than a second light transmittance of the color filter layer in a portion of the cholesteric layer away from the optical window portion.